This invention relates to a combination sofa-sleeper bed, and, more particularly, to an improved sofa-sleeper deck structure.
Sofa-sleepers are well known in the prior art. Basically, a sofa-sleeper includes a foldable bed frame which supports a mattress when the bed frame is extended to a generally flat, bed configuration. The sofa-sleeper is adapted for use as a sofa when the bed frame is folded up into a storage configuration within the framework of the sofa to permit use of the structure as a seating surface. One such prior art sofa-sleeper is illustrated in U.S. Pat. No. 3,954,153 issued on Dec. 17, 1974, and assigned to the assignee of this invention.
Sofa-sleeper structures known in the prior art generally include a wire mesh or wire grid attached to the foldable bed frame. The wire grid either extends the full length of the foldable bed frame or a major portion thereof, the remainder being made from cloth, as disclosed in U.S. Pat. No. 2,878,490 issued to Schneider. This wire grid, or wire and cloth grid, is generally connected with the sides and at least one end member of the bed frame by a plurality of tension springs in order to maintain the grid in a taut and partially resilient posture when the frame is unfolded for use as a bed.
However, whether the sleeping surface of a sofa-sleeper is constructed from wire only or from wire and cloth, it has always been considered a compromise and a less satisfactory sleeping surface than a standard bed. Primarily, the shortcoming of a sofa-sleeper deck has been the tendency of the wire grid to sag when a person rests prone atop the unfolded bed. The wire grid, or wire and cloth grid, does not maintain the sofa-sleeper deck in a sufficiently taut and resilient manner to avoid sagging of the unfolded sofa-sleeper.
One prior art solution to the problem of sag in a sofa-sleeper deck is described in U.S. Pat. No. 4,584,727 which discloses a sofa-sleeper deck wherein the deck is divided up into head, body, intermediate and foot sections. The foot section is comprised of a plurality of sinuous wires; whereas, the remaining sections can be constructed of plywood as either solid panels, individual slats, or pairs of slats. However, the problem associated with a sofa-sleeper deck of such construction is that the panels constructed of plywood are excessively rigid and therefore uncomfortable for sleeping. Furthermore, a sofa-sleeper constructed with such a deck is extremely heavy, costly, and difficult to move and transform to and between the sofa configuration and the sleeper configuration.